Typically, in the manufacture of semiconductor devices or the like, a shower head has been used to supply a gas toward a substrate such as a semiconductor wafer or the like in a form of shower. For example, in a plasma processing apparatus for performing a plasma etching process on a substrate such as a semiconductor wafer or the like, a mounting table for mounting the substrate thereon is provided inside a processing chamber and a shower head is provided to face the mounting table. In the shower head, a plurality of gas injection holes is formed on a facing surface that faces the mounting table and a gas is injected toward the substrate through the gas injection holes in a form of shower.
In the plasma processing apparatus, since a plasma is generated in the processing chamber, the temperature of the shower head is increased. For this reason, there has been disclosed a plasma processing apparatus in which a fan or the like is provided to air-cool the shower head (see, e.g., Japanese Patent Application Publication No. 2003-068710). Moreover, there has been disclosed a plasma processing apparatus in which the shower head is cooled by allowing a temperature control medium to be circulated therearound (see, e.g., Japanese Patent Application Publication No. 2006-352040).
The above-described plasma processing apparatus cooling the shower head by the air cooling or the circulation of the temperature control medium is configured to exhaust the processing chamber from a lower portion thereof. In the meantime, the present inventors have been developing a shower head serving as not only a gas supply unit through which a gas can be supplied but also a gas exhaust unit having a plurality of gas exhaust holes through which gas exhaust is performed, to thereby improve the uniformity of gas flow.
However, if a mechanism for performing the cooling by circulating a coolant is applied to the shower head serving as both the gas supply unit and the gas exhaust unit, it would cause paths of the gas exhaust holes to extend, thereby deteriorating the exhaust performance.
Further, since such a shower head requires a cylindrical member (exhaust line) constituting an exhaust path above the shower head, it is difficult to provide an air-cooling unit for directly cooling the shower head. For that reason, the temperature of the shower head would be increased and the temperature distribution of the shower head may also become nonuniform, thereby deteriorating the uniformity of processing.